Improvement in hand-clamps



S. L. THOMPSON.

Improvement in Hand-Ciamps.

NO. 126,425. Patented May7,"|872..

71 5672 ass as.

In Yen/ ar zm m UNITED STATES STEPHEN L. THOMPSON, OF LOWELL,MASSACHUSETTS.

IMPROVEMENT IN HAND-CLAMPS.

Specification forming part of Letters Patent No. 126,425, dated May 7,1872.

To all whom itonay concern:

Be it known that I, STEPHEN L. T110111 SON, of Lowell, in the county ofMiddlesex and State of Massachusetts, have invented certain new anduseful Improvements in Hand- Glamps, of which the following is a full,clear, and exact description, reference being had to the accompanyingdrawing making part of this specification, in which- Figure 1 representsa side elevation, partly in section, and Fig. 2 an end view of thetightening-screw, with the crank or wrench, and the means for applyingand using the same.

This invention and improvement in a handscrew consists of the screw A,provided with a collar, B, in combination with wrench G, screw D, jawsE, as shown in the drawing, the collar being squared, or otherwisefitted for the application of the crank or wrench, and applied to thehandle of the screw A by a tenon, a, formed thereon, or by othersuitable and equivalent means.

The hand-clamp is constructed in the usual way, and the inner screw Dremains unchanged but on the end of theahandle of the outer ortightening-screw a square tenon, c, is formed, and upon this tenon thecollar B is applied, the hole in the collar fitting firmly and closelyto the tenon, the parts being driven or forced together, and generallyrequire no fastening to hold them. A suitable crank or wrench, (l,beingfittedto the collar or nut, the clamp is applied to the object tobe pressed or held together, with the inner screw set to hold the clampin position, as usual, when the crank or wrench is applied to the collarB, and the screw may be turned rapidly and with greater force, owing tothe leverage of the crank, than can be done by hand. The crank orwrench, in connection with the collar or nut, is also useful inreleasing the screw-clamp from the object, and will facilitate theprocess of releasing as well as of applying the clamp. The flangedof thecollar serves to protect the wood handle, and makes a broader shoulderand more firm bearing for the collar, and greatly strengthens the latterto resist the action of the crank when force is applied to turnthescrew.

My said invention possesses a still further advantage in the matter ofits utility, and to a certain degree of its novelty, which is asfollows: If by accident or too great a strain upon the tenon covered bythe flanged collar said tenon should be broken 011' or materiallyinjured, a new tenon may be easily formed below the former one, and thecollar applied to the newly-formed tenon, and this may be repeatedseveral times, and thus preserve the tightening-screw, and maintain itsefficiency in a very cheap way.

What I claim as my invention, and desire to secure by Letters Patent,is-

In a hand-screw, the screwA provided with collar B, in combination withwrench G, screw D, andjaws E, in the manner and for the purpose shownand described.

STEPHEN L. THOMPSON.

Witnesses:

J OHN E. CRANE, GEo. M. MUNN.

